JPS60223685A - Laser welding method - Google Patents

Abstract

PURPOSE:To perform welding with high accuracy and decreased man-hour by superposing a preceding metallic sheet and a succeeding metallic sheet to two layers, cutting the sheets by a laser beam, butting the cut ends to each other and welding the butt parts by the laser beam. CONSTITUTION:The preceding metallic sheet 1 and the succeeding metallic sheet 2 are superposed into two layers and are clamped by a clamp 3 on an outlet side and a clamp 4 on an inlet side. Oxygen is supplied in this state to a gas supply port 8 of a laser working head 7 then the sheet 1 and the sheet 2 are cut by the laser beam. The clamp 3 and the clamp 4 are moved to butt the cut faces of the sheet 1 and the sheet 2. Gaseous argon or helium is supplied to the port 8 of the head 7 and the head 7 is moved on a weld line 9 to weld the butt ends by the laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a laser welding method for welding metal plates, particularly steel strips and thin steel plates, with a laser beam.

[Prior art]

Laser welding, which welds metal plates with a laser beam, can weld with a heat source of high energy density, so the fusion width can be extremely small, and the welding speed can be fast.1) - Butt welding of steel strips and thin steel plates It can be used when

10,000, since the spot diameter of the laser beam is very small,
When abutting metal plates, the linearity of the abutting surfaces of the leading metal plate and the trailing metal plate requires high precision. That is, the spot diameter d of the laser beam is given by the following equation.

d = 2 x 1.22λ- where λ is the wavelength of the laser, f is the focal length of the condenser lens,
D is the diameter of the laser beam incident on the condenser lens.

For example, when a carbon dioxide laser with a wavelength λ of 10.6 μm is used and the aperture ratio (f/l) is 20, the spot diameter d of the laser beam is approximately 52 μm. Therefore, in this case, the linearity of the weld between the leading metal plate and the trailing metal plate is 50μ
Requires accuracy of less than m. Furthermore, it is necessary to align the welding line and the spot locus of the laser beam with an accuracy of 50 μm or less, as described above.

For this reason, conventionally, a double cut shear having an upper shear (5) and a lower shear (6) is used as shown in FIG.
After cutting the end of the trailing metal plate (2) clamped with the entry clamp (4) with high precision, move the exit clamp (3) or the entry clamp (4) to cut the leading metal plate (1). and the trailing metal plate (2) are butted against each other and aligned with the laser processing head, and laser welding is performed.

However, a double cut shear that produces highly accurate straightness of the cutting portion has a complicated structure and is expensive. Furthermore, in order to butt the cut parts of the leading metal plate (1) and the trailing metal plate (2), an exit side clamp (3) or an input side clamp (4) is used.
The distance to move is long, and therefore there is also the problem that it is not easy to align the welding line with the laser processing head.

[Summary of the invention]

This invention was made for the purpose of improving the above-mentioned problems. 6D, a leading metal plate and a trailing metal plate are stacked and clamped, and cut with a minute spot of a laser beam, and the cut portion is punctured. This paper proposes a laser welding method that enables highly accurate welding by welding the abutted parts with a minute spot of the same laser beam after matching.

[Embodiments of the invention]

1 and 2 show the apparatus used to carry out the present invention, FIG. 1 is a schematic configuration diagram when cutting the ends of the leading metal plate (1) and the trailing metal plate (2), and FIG. 1 shows a schematic configuration diagram when butt welding a leading metal plate (1) and a trailing metal plate (2).

When welding the leading metal plate (1) and the trailing metal plate (2), as shown in Figure 1, the leading metal plate (1) and the trailing metal plate (2) are welded.
Clamp 2) with the exit side clamp (3) and the entry side clamp (4) in a stacked state. In this state, oxygen is supplied from a processing gas supply device (not shown) to the processing gas supply port (8) of the laser processing head (7), and the leading metal plate (1) and trailing metal plate (2) are exposed to the laser beam. disconnect. This greatly improves the precision of both cutting surfaces and the cutting speed.

After cutting the leading metal plate (1) and trailing metal plate (2), move the exit clamp (3) and the input clamp (4) to 1 part of the cutting width.
/2 movement, and as shown in FIG. 2, the cutting surfaces of the leading metal plate (1) and the trailing metal plate (2) are brought into contact with each other. In this case, since the moving distance of both metal plates is short, it is easy to align the weld line (9) with the laser processing head (7).

Next, the solenoid valve of the processing gas supply device (not shown) is switched to supply argon gas or helium gas to the processing gas supply port (8), and while moving the laser processing head (7), the weld line (
9) Weld the top with a laser beam.

The trajectory of the laser processing head (7) during welding matches the trajectory of the laser processing head (7) during cutting, so the trajectory of the welding line (9) and the laser processing head (7) during welding. alignment is not required.

After welding, remove the exit clamp (3) and the entry clamp (4).
), it is possible to supply a continuous metal plate.

〔Effect of the invention〕

As explained above, this invention cuts two stacked metal plates with a laser beam and then welds the cut surfaces with a laser beam, eliminating the need for a high-precision double cut shear and eliminating the need for welding lines. It is easy to align the laser processing head, and there is no need to align the movement locus of the laser processing head. Therefore, it is possible to perform high-precision welding with a low number of man-hours, and at the same time, the equipment used can also be used at a low cost.

[Brief explanation of the drawing]

1 and 2 show an apparatus used in an embodiment of the present invention, FIG. 1 is a schematic configuration diagram of the apparatus for cutting a metal plate, and FIG.
The figure is a schematic diagram of a metal plate welded, and FIG. 3 is a schematic diagram of a conventional double cut shear. (1)... Leading metal plate, (2)... Trailing metal plate, (
3)... Output side clamp, (4)... Input side clamp,
(5)...Upper shaft, (6)...Lower shaft', (7
)...Laser processing head. Note that the same reference numerals in each figure indicate the same or equivalent parts. Agent Patent Attorney Sanro Kimura

Claims (1)

[Claims] In laser welding, which welds metal plates with a laser beam,
A laser welding method comprising stacking two leading metal plates and a trailing metal plate and cutting them with a laser beam, and then abutting the cut parts and welding them with the laser beam.